The sections of the polypoid skin lesion showed dermal cords and trabeculae of uniform basaloid cells (Figure 2) extending from the underside of the epidermis. The tumor cells showed diastase-sensitive periodic acid–Schiff–positive staining, with areas of melanin pigmentation, squamous differentiation, and focal ductule lumina (Figure 3). Occasional mitoses were seen but none were abnormal. The surrounding paucicellular stroma contained prominent, often ectatic, small-diameter blood vessels. The features are typical of an eccrine poroma.
A Solitary Tumor of the Left Temple. Arch Dermatol. 1999;135(4):463-468. doi:10-1001/pubs.Arch Dermatol.-ISSN-0003-987x-135-4-dof0499